The present invention relates to an optical switching network.
Two key challenges faced by existing data center network (DCN) architectures are (a) balancing the demand for high bandwidth connectivity between all pairs of servers with the associated high cost, and (b) having the flexibility to support a variety of applications and their traffic demand.
Many online services, such as those offered by Amazon, Google, FaceBook, and eBay, are powered by massive data centers hosting tens to hundreds of thousands of servers. The network interconnect of the data center plays a key role in the performance and scalability of these services. As application traffic and the number of hosted applications grow, the industry is constantly looking for larger server-pools, higher bit-rate network-interconnects, and smarter workload placement approaches to effectively utilize the network resources. To meet these goals, a careful examination of traffic characteristics, operator requirements, and network technology trends is critical
High bandwidth, static network connectivity between all server pairs ensures that the network can support an arbitrary application mix. However, static network topologies that provide such connectivity tend to be quite expensive (in terms of both the startup as well as recurring costs), and cannot scale beyond a certain number of interconnected servers. Further, for many applications, all-to-all connectivity at all times is not needed, and hence static network connectivity can be quite wasteful in these cases. Finally, such topologies also suffer from the need to “re-wire” the network to support greater network bandwidth demands from future applications.
Existing DCN architecture proposals attempt to address these challenges by using a hybrid approach that combines small-scale, all-to-all connectivity using electrical interconnects with alternative data transmission technologies (e.g. high-speed wireless or optical switching) that provide flexibility in terms of adapting to traffic demands. In these approaches, the workload is split between the electrical and optical network paths such that peak traffic is offloaded to the extra paths (could be wireless/optical/electrical). This use of optical or wireless transmission technologies as an add-on, as opposed to a fundamental component of the architecture, limits the applicability of these solutions to today's network traffic patterns and bandwidth demands—the base network topology is not flexible and is built on the assumption that average traffic patterns are known in advance. In addition, these solutions also suffer from the need to re-wire the electrical network to support higher throughputs.